Update black and isort for embed_video and example_project

[mgrdcm]

Also includes necessary changes to get to pass, and ignores example_project's migrations.

Pulled and slightly modified from @mahdirahimi1999's #214.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.10%. Comparing base (847d077) to head (30c4a2a).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #227   +/-   ##
=======================================
  Coverage   99.10%   99.10%           
=======================================
  Files          16       16           
  Lines         671      671           
  Branches       40       40           
=======================================
  Hits          665      665           
  Misses          4        4           
  Partials        2        2           

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